The so-called steel, generally divided into profiles, plates, pipes and metal products in these four categories, in general, structural steel is usually used for construction, bridges, ships, boilers or other engineering production of metal structural steel. Such as carbon structural steel, low alloy steel, steel and other steel. Structural steel for machine construction generally refers to steel used to make structural parts on machinery and equipment. Such steel is basically high-quality steel or high quality steel, there are high-quality carbon structural steel, alloy structural steel, free-cutting structural steel, spring steel, rolling bearing steel. The tool steel is generally used to make a variety of tools, such as carbon tool steel, alloy tool steel, high-speed tool steel. The use of tool steel can be divided according to the purpose of cutting tool steel, die steel, measuring steel. There are some special steel, the so-called special steel is a steel with special properties, such as stainless steel, heat can not afford skin leather, high resistance alloy, wear-resistant steel, magnet.

The so-called aluminum, aluminum rod is hot melt, extrusion, resulting in different cross-sectional shape of the aluminum material. The aluminum can usually be divided into architectural aluminum, aluminum radiator, general industrial aluminum, rail vehicle structure aluminum profiles, mounted aluminum and so on. The use of aluminum is also more extensive, especially in the large number of industrial manufacturing.

The overall is simple, high hardness steel, high temperature, good processing performance, the proportion of large, tensile resistance to shear stress; and aluminum is low hardness, good ductility, corrosion resistance, light weight, electrical conductivity it is good.